Effect of Ferrous Ions on Oxide Film Formation and Conversion on Stainless Steel

Abstract

The effect of the presence of dissolved ferrous ions (Fe 2+ (aq)) on oxide film growth and conversion on Type-316L stainless steel in pH 8.4 borate solutions was studied by a range of electrochemical and surface imaging and spectroscopic analysis techniques. The results provide a consistent picture of the anodic oxidation behavior of the stainless steel surface. At potentials below −0.3 V SCE , the rate of oxidation is somewhat decreased by the presence of Fe 2+ (aq) in solution. At potentials > −0.3 V SCE , the presence of Fe 2+ (aq) in solution substantially increases the formation of γ-FeOOH via oxidation of Fe 2+ (aq) at the oxide/water interface.

Potentiostatic Oxide Growth Kinetics on Ni-Cr and Co-Cr Alloys: Potential and pH Dependences

“…At 13 nm the value of (2 Â Cr)/(Ni + Fe + 1.5Cr) is 0. 24 We can use the observed oxygen ratio, O/(Ni + Fe + 1.5Cr), to determine the likely mixture of oxides present as a function of depth by matching the ratio to the calculated oxygen ratio that would arise for those oxides. Table 2.…”

“…This spans potentials for reducing deaerated water to highly oxidizing water (e.g., that containing H 2 O 2 or water exposed to ionizing radiation), while remaining within the water stability range [4,5,24]. The polarization experiments were performed at three different pH 25 C values (6.0, 8.4 and 10.6) and at two different temperatures (25 and 80 C).…”

Mass and Charge Balance (MCB) Model Simulations of Current, Oxide Growth and Dissolution during Corrosion of Co-Cr Alloy Stellite-6

“…The nature of oxide and the oxide layer structure can also change with time as corrosion progresses even under potentiostatic polarization or constant solution conditions. [8][9][10][12][13][14][15][16][17] The type of oxide that can form and its rate of formation depend on solution environmental parameters such as pH, temperature and the concentrations of redox active species. Few existing models specifically incorporate the solution environment in their model parameters and, even in those models that do so, the effects are formulated primarily based on empirical relationships.…”

“…Alloys owe their corrosion resistance to protective oxide films formed on their surfaces. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Corrosion involves surface redox reactions (metal oxidation coupled with solution reduction) and interfacial transfer of the charged species involved in the redox reactions. The presence of an oxide film hinders the interfacial charge transfer, slowing the rate of corrosion.…”